Electric switch



Dec. 4, 1928.

J. D. HILLIARD ELECTRIC SWITCH Filed March 17, 1924 8 W a o .L 7 m 3 .7 NW/I/ l w 5 3 5 6 Z 4, A! 1: 2 9 4 m I: 5% :3

Patented Dec. 4, 1928.

UNITED STATES PATENT OFFICE.

JOHN D. HILLIARD, OF SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Application filed March 17, 1924. Serial No. 699,689.

My invention relates to electric switches and particularly to switches for the control of high potential electric circuits. An object of my invention is to provide an improved l switch of the liquid type which is adapted to open the circuit automatically upon the occurrence of a predetermined overload and which is of a simple and inexpensive construction whereby it ma be substituted in many instances where uses are now employed.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and

its scope will be pointed out in the appended claims.

In the drawing, Fig. 1 is a longitudinal cross sectional view of a switch embodying my invention; Fig. 2 is a fragmentar cross sectional view of a modified form an' Fig. 3 is a side elevation of the complete switch showing the means by which it is mounted and connected.

Referring first to Fig. 1 the body of the 5 switch comprises a tube 1 which may be of class, a phenol-condensation product such as akelite, or similar substance. The lower portion of this tube is shown cemented in a socket member 2 to which is secured by suit- 8 able bolts 3 a tubular metal member 4 whose lower end is closed by bein screw-threaded into a supporting cap 5. 'lfiie joint between members 2 and 4 may be made tight by the use of a suitable gasket 6 constructed for example of cork and a similar gasket may be used if desired between the member 4 and the ca 5.

, lidably mounted on the exterior of the tube is a coil 9 which is shown adjustably sethree screw-threaded rods 10 which pass through lugs 11 formed on the socket member and which are held in adjusted position by nuts 12. 'Above the coil 9 is a contact ring 14,

- shown cen'iented to the body 1,'and at the upper end of the body is a second contact ring 15, also shown cemented to the body. This second ring 15 has an annular groove formed in its upper face which contains a sealing liquid, such for example as mineral oil. cap 16 of conducting material having con tact fingers 17 secured thereto fits overfthe outer end of the body 1 and is resiliently held in place by the flange portion 18 which'if de- 5 cured to the socket member 2. by means of.

sired may be slitted longitudinally to fotm' fingers to increase its resiliency. These fingers 17 constitute what corresponds to the usual stationary contact. An outer cap 20,

shown as comprising two plates secured together and eac havin a flanged edge, covers the top. The inner ange 21 dips into the sealing liquid while the outer flange 22 fits over the upper contact ring 15. Within the body 1 is a supporting member 24, shown secured to the socket member 2 by means of bolts 25. Guided by this member 24 is the rod 26 which at its upper end carries the contact 27 which is wlthdrawn from the fingers 17. At its lower end it is secured to the cap 5 by means of a coil spring 28, which when the two contacts are in engagement, as illustrated, is held under tension. The one end of the spring 28 is secured to the rod 26 by means of the block 29'while the opposite end is secured to the cap 5 by means of the block 30. To provide a flexible current carrying path other than the spring between the cap 5 and the rod 26, the pig tail 31 is provided which is shown extending within the spring. For retaining the contact carr ing rod 26 in its raised position against t e tension of the spring 28 a spring pressed latch 32 is provided and arranged to engage in a notch33 formed on the rod 26. The latch is pivotally supported on the member 24 and has a portion 34 extending laterally and downwardly to a point below the member 24. The hollow magnet plunger 35 is mounted to slide on the rod 26 and .when raised by the energization of the coil- 9 engages the portion34 and trips the latch.

As shown in Fig. 3 the device is sup orted by an insulated post 37 which is pivote at 38 to the cap 5. It is held in an upright position and electrically connected in the circuitby spring clips 39 and 40 which are supported by post insulators 41 and 42 and which have terminals 43 and 44. Contact ring 14 is connected by flexible lead 45 to one, end of coil 9 and the other end of the coil is connected to the member 4 by flexible lead 46. I

The. body 1 and member 4 are filled to th level indicated by the dotted line with an arc extinguishing liquid as for exampleoil, carbon tetrachloride, or a mixture of water and glycerine, the latter being preferred. -When the current traversin the coil 9 reaches a predetermined value t e plunger is suddenly pulled up, striking the latch and rod 26. As the contact 27 descends an arc is drawn down into the liquid and the gas and steam thus formed create suificient pressure to blow off the caps 16 and 20.

To reset the switch a, suitable tool having a hook may be inserted in the top of the body so as to engage under the contact 27 and raise the rod 26 until it latches. Additional liquid may be added to the body 1 to bring the level to the desired height and additional sealing liquid may be added to the sealing groove. The same or other top ca s 16 and 20 may then be pushed in place, is iereby closing the circuit between rings 14 and 15 and putting the switch in readiness for another operation. In resetting the switch it may be found preferable to remove it from the lower supporting member 37 and to finally make contact by means of a switch hook or by closing an auxiliary disconnecting switch. By varying the vertical position of the coil 9 the value of current at which the switch will operate to open the circuit may be varied.

In the modification illustrated by Fig. 2 the upper contact ring 15 is constructed with a portion &8 extending within the body 1 and the inner or contact carrying cap is constructed to fit within and to be permanently secured to this portion 48 as illustrated. A suitable tool may be inserted in the spaces 49 for resetting the switch. With this form of switch the outer cap only is blown ofi when the switch opens as a result of an overload.

lVhile I have described certain embodiments only of my invention, I do not wish to be limited to the particular forms shown and described as it will be apparent that many modifications therein may be made without departing from the scope of my invention as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. A switch of the character described comprising a tubular insulating supporting member containing an arc extinguishing liquid, a conducting ring at the upper end of said member having an annular groove in its upper face, a sealing liquid in said groove, a contact in said supporting member connected .with said ring, a coo crating contact in said member adapted to e separated from said first member and submergedin said liquid, and a removable cover for said parts having a flange portion dipping into said sealing liquid.

2. A switch of the character described comprising a tubular member of insulating material, an arc extinguishing liquid therein, a cover for the top of said member constructed and arranged to be blown off by gas pressure within the member, a contact carried by said cover, a coo crating contact mounted in said member and biased to move away from said first contact, latching means for restraining said movement, and current responsive means for releasing said latch com rising a coil mounted exteriorly of said to ular member and a plunger mounted within said member.

3. An electric switch comprising a hollow supporting member containing an arc extin guishing liquid, 2. cap coverin the top thereof, a fixed contact secured to t 1e cap, a coopcrating movable contact mounted within the member, means for withdrawing the movable contact from the fixed contact and current responsive means for releasing the movable contact, said cap and fixed contact being adapted to be blown bodily from the supporting member upon the occurrence of a predetermined pressure therein. I

4. An electric switch comprising a. hollow supporting member containing insulating liquid, a contact ring thereon, a cap covering the top of said member and havin a flange portion detachably engaging sai ring, a fixed contact secured to the cap on the inner side thereof, a cooperating contact within the member, a spring for withdrawing it from the fixed contact, and a load responsive latching device within the member for releas ing the spring.

In witness whereof, I have hereunto set my hand this 15th day of March, 1924-.

JOHN D. HILLIARD. 

